Changeable tip tweezers and the like

ABSTRACT

Changeable tip tweezers formed of a handle portion having a pair of resilient arms extending in a V-shaped path from a heel end and terminating in outwardly opening channel recesses, receiving substantially wedge shaped mounting formations on the rear ends of changeable tips. The surfaces of the mounting formations are engaged and positioned by confronting surfaces of the channel recesses to precisely aline the tips, and enlarged circular nut members of larger diameter than the vertical width of the tweezers hold the tips on the handle portion and provide rest supports and finger discs.

United States Patent [191 McClure June 25, 1974 CHANGEABLE TIP TWEEZERSAND THE LIKE [75] Inventor: Edgar M. McClure, Roanake, Va. [73]Assignee: Scientific Components Inc.,

Roanoke, Va.

[22] Filed: Jan. 3, 1973 [21] Appl. No.: 320,817

[52] 11.8. C1. 81/43 [51] Int. Cl B25b 9/02 [58] Field of Search 81/43;128/354; 294/99 [56] References Cited UNITED STATES PATENTS 1,758,4905/1930 Aderer 81/43 2,764,905 10/1956 Thoms 81/43 2,833,239 5/1958Larsten, 81/43 X FOREIGN PATENTS OR APPLICATIONS 348,130 9/1960Switzerland 81/43 769,917 3/1957 Great Britain 128/354 561,890 10/1932Germany ..8l/43 Primary Examiner-Othell M. Simpson AssistantExaminerRoscoe V. Parker Attorney, Agent, or Firm-Mason, Fenwick &Lawrence [57] ABSTRACT Changeable tip tweezers formed of a handleportion having a pair of resilient arms extending in a V-shaped pathfrom a heel end and terminating in outwardly opening channel recesses,receiving substantially wedge shaped mounting formations on the rearends of changeable tips. The surfaces of the mounting formations areengaged and positioned by confronting surfaces of the channel recessesto precisely aline the tips, and enlarged circular nut members of largerdiameter than the vertical width of the tweezers hold the tips on thehandle portion and provide rest supports and finger discs.

9 Claims, 6 Drawing Figures CHANGEABLE TIP TWEEZERS AND THE LIKEBACKGROUND AND OBJECTS OF THE INVENTION The present invention relates toimprovements in tweezer type instruments for facilitating picking up,handling, and/or inspection of small articles, and more particularly toprecision tweezers for use in handling tiny components, wherein the jawportions of the tweezers forming the tips or points are readilyremovable from the arms of the tweezers for repair, sharpening, orreplacement with like or different shaped tips and wherein thechangeable tweezer tips are accurately held so that precise point matchis achieved at the outer ends of the tips.

In the manufacture of many articles, components which are required to beinspected, or picked up and handled by workmen are so small that greaterprecision in the construction and operating characteristics of thetweezers are required than are available in ordinary commercialtweezers. For example, in the electronic industry, tweezers or similarinstruments are required for handling discs such as the germanium andsilicone wafers without scratching the semi-conductor wafers, and whichpermit easy pick-up and safe gripping of the semi-conductor wafers. Manyof the miniature, or micro-miniature electronic parts are highlyfragile, and expensive or costly losses are sometimes suffered fromaccidental dropping or release of such components. Most frequently, theaccidental dropping of the components being handled by tweezers occursbecause of end flexing of the tweezer points, wherein the outermost endsof the tweezer points or tips become separated somewhat from each otherwhen the tweezer handles are overstr'essed toward each other andengagement of portions of the tweezer tips spaced about a half-inch orso back of the ends of the points produces a bowing of the tweezerpoints or tips distorting the outermost ends away from each other. Thisdistortion or end flexing may produce sufficient separation to releasethe item being held between the tweezer points. Also this characteristicof many tweezers of end flexing makes it very difficult to pick upextremely thin items such as paper, because the outermost ends of thetweezer tips or points may be distorted away from each other a greaterdistance than the thickness of the paper or thin sheet material to begrasped.

Also, in handling tiny watch parts or jewelry components, and formanipulating such tiny parts, as in straightening or bending hairsprings for watches, the tweezers must have very slender points, whichare delicate and easily dulled, and are subjected to breakage if extremecaution is not exercised when the tweezers are laid down on the workbench. In conventional tweezers, the points are made integral with thearms of the tweezers,'and if dulled or broken, can be properlyresharpened only by someone highly skilled in that procedure and at theexpense of considerable time and cost. Provision of removable tips orpoints facilitates removal and installation of a new set of tips by theuser with minimum expense and loss of time. However, it has beendifficult to insure that tweezer tips which are removably secured tohandles, when being replaced for any reason, maintain such accuratealinement with the handle and preserve their original position relativeto their companion tips that precise point match is maintained.

Also, manufacturing operations involving handling or inspection ofminiature components frequently require a number of different types oftweezer tips for effective access to and handling of the miniaturecomponents. in some cases, long very pointed tips are required, withflat confronting surfaces, while in other situations, angled or curvedtips of various configurations, or tips with concave or convex ends maybe required for particular applications. Economies in manufacture offine precision tweezers and components therefor can be achieved wheresuch situations exist, by supplying a number of different configurationsof precision manufactured tip portions for tweezers in various shapesand configurations, without having to manufacture an entire pair oftweezers for each tip shape. Thus standardized handles with a number ofdifferent tip configurations permits economies to be realized in themanufacture of the tip portions only.

Also, conventional tweezers suffer the disadvantage of tending to skewwhen pressed together, so that the end portions of the points or tips donot precisely match up but become shifted out of precise alinement andcross each other slightly. To avoid this problem, as well as the problemof end flexing, precision tweezers for industrial handling of miniaturecomponents and for medical uses in other precision applications aregenerally much heavier on the end portions of the points and haverequired precision grinding to file them down to exactly true positionsand configurations. This can be more effectively and economicallyachieved where the tweezer tips are formed as separate components whichare later assembled to the arms of the tweezer handle portions, so thatonly the tip portions need to be shaped and processed to produce thedesired precision configuration and surface characteristics.

An object of the present invention, therefore, is the provision of anovel tweezer construction having changeable tips or points separablyconnected to the ends of the arms of the tweezer handle portions,wherein the tips are coupled to the tweezer handle arms by a novelconstruction insuring precise alinement of the changeable tips with eachother to achieve exact point match, and wherein the tweezer tips may beseparably manufactured and processed in a way to minimize end flexing orskewing of the tweezer tips during use.

Another object of the present invention is the provision of a novelchangeable tip tweezer construction as described in the immediatelypreceding paragraph, wherein finger discs form removable portions of thecoupling structure for mounting the changeable tweezer tips on the armsof the tweezer handle portion, facilitating supporting of the tweezersin a manner protecting their tips when the tweezers are at rest on awork bench or the like and also inducing users to hold the tweezers in aconsistent position which facilitates always picking them up andpositioning them in a particular way.

Other objects, advantages and capabilities of the present invention willbecome apparent from the following detailed description, taken inconjunction with the accompanying drawings illustrating preferredembodiments of the invention.

BRIEF DESCRIPTION OF THE FIGURES FIG. 1 is a perspective view of oneembodiment of changeable tip tweezers constructed in accordance with thepresent invention, with one of the tweezer tips or points and thecoupling disc therefor shown in exploded relation;

FIG. 2 is a side elevation view of the changeable tip tweezers;

FIG. 3 is a top plan view of the changeable tip tweezers;

FIG. 4 is a vertical transverse section view, taken along the line 4-4of FIG. 2;

FIG. 5 is a fragmentary horizontal longitudinal section view through thecoupling mechanism associated with one arm of the tweezers, taken alongthe line 55 of FIG. 2; and

FIG. 6 is a perspective view similar to FIG. 1, but having tweezer tipswhich are of a different form from those illustrated in FIG. 1.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Referring to the drawing,wherein like reference characters designate corresponding partsthroughout the several figures, and particularly to the embodiment ofFIGS. I through 5, the tweezers of the present invention are indicatedgenerally by the reference character 10 and include a handle portion 12of customary configuration having a pair of resilient arms 14 that maybe substantially identical, having the butt ends or heel portions joinedtogether in the conventional manner to provide a heel end 16. The twoarms 14 diverge outwardly from the heel end portion 16 in a shallow V-shaped configuration, when viewed in top plan, and terminate in endformations I8 specially shaped and formed to facilitate removablemounting of tweezer tips 20 thereon. The elements herein referred to astips or tweezer tips are also customarily referred to in the trade aspoints or jaw portions of tweezers. In the embodiment illustrated inFIGS. 1 to 5, the tweezer tips 20 are straight, tapered, sharpened orpointed tips 20 having flat inner faces of triangular profileterminating in sharply pointed outer ends 24 and having mountingportions 26 at the base ends thereof which are substantially wedgeshaped formations of rectangular lateral profile defining outer faces26a which converge rearwardly or toward the heel end of the tweezersrelative to the rearwardly diverging, opposed confronting faces 22 ofthe tip portions and lie in substantially parallel planes when thetweezer arms occupy their normal, unstressed diverging positions. Therearward mounting portions 26 of the tweezer tips 20 are each providedwith a single aperture 26b extending therethrough along an axisperpendicular to the plane of the outer face 26a.

To accurately position the tips 20 exactly in their properly alinedrelation with the opposing confronting faces 22 converging forwardly inthe proper planes or paths so that they meet at the outer ends 24 withprecise point match, the end formations 18 of the handle portions 12 areformed with broached channel shaped kerfs or recesses 28 which openoutwardly through the outer faces of the associated handle arms 14 andopen through the forward ends of the respective handles, as best shownin FIG. I. The channel shaped kerfs or recesses 28 are shaped to defineconfronting channel sides 28a of triangular configuration accuratelyconforming to the vertical spacing between the upper and lower parallelsurface portions 26c of the rectangular wedge shaped mounting portions26, while the base wall 28b of each of the kerfs or recesses 28 isrectangular in lateral profile corresponding exactly to the portion ofthe opposing confronting faces 22 of the tips to be nested in thechannel shaped recesses. The base walls 28b of the channel shapedrecesses 28 lie in forwardly converging planes which conform exactly tothe desired planes in which the opposing confronting faces 22 of thetips are to lie, so that exact location and disposition of the tips 20is achieved by the nesting of the mounting portions 26 in the channelshaped recesses 28. The proper convergence of the tip members and theproper axial alinement of the tip members with the desired high degreeof precision is attained in a very accurate, but inexpensive way bybroaching the end portions of the handle arms 14 with the handle held ina jig which clamps the handle arms 14 securely at the proper normalangular position, preferably with the handle arms diverging upwardly ina vertical position, and relatively moving twin broaches downwardly fromabove the jig mounted handle portion to remove the necessary materialfrom the upper end portions of the jig supported handle arms as thebroaches move relatively downwardly and thereby precisely form the wedgeshaped channel 28 in the outwardly facing portion of each of the twohandle arms 14.

The tips 20 are held in the channel recesses 28 in the handle arms 14 bythreaded screws or studs 30 fixed in a conventional manner to themounting portions 26 of the handle arms 14, which extend through theapertures 26b in the mounting portions 26 of the respective tips 20 andare threaded into threaded openings 32a in slightly concave disc members32 of considerably larger diameter than the maximum vertical dimensionof the handle arms when viewed in side elevation in the horizontalposition, as shown in FIG. 2. The disc members 32 form convenient fingerdiscs for engagement between the pads of two fingers of the users hand,for example the thumb and index finger, for manipulation of the tweezersso as to bring the outer ends of the tips or points together or separatethem, while the heel portion of the handle 12 rests against the base ofthe little finger in a crook formed by the curled little finger of theuser's hand. To this end, the large disc formations 32b of the discmembers 32 are outwardly concave to present inwardly dished circularsurfaces to the users fingers, while smaller diameter hub portions 32cextend inwardly concentric with the threaded openings 32a and terminatein flat cylindrical surfaces to bear against the outer faces 26a of themounting portions of the tips and tightly clamp the tips in the channelrecesses 28. Also, the larger diameter disc fonnations on the discmembers 32b, which have knurled peripheries to facilitate rotation ofthese disc members, serve as a pair of convenient supporting formationsto form with the heel end portion 16 the three contact portions of athreepoint supporting contact for the tweezers on a work bench orhorizontal supporting surface to maintain the precisely ground endportions of the tip out of contact with the work surface and minimizepossibility of damage to the working end portions of the tips.

In the illustrated example, the threaded screws 30 are fonned withrectangular, slightly enlarged head portions 30a seated in confonningrecesses in the confronting faces 22 of the handle, with the headseither loosely fitted in the recesses or permanently fastened therein asby spot welding, or press fitting, or any other desired, known fasteningtechnique.

FIG. 6 illustrates a modified version of the tweezers, wherein thehandle portion 12 is the same as in the preceding embodiment andincludes the pair of diverging, resilient arms 14 joined together at theheel or butt end 16 and having the channel shaped recesses 28 in thefront ends thereof formed in the same manner as in the previouslydescribed embodiment. The tips or jaw members, however, in thisembodiment are angled tips or angled points, indicated generally by thereference character 40, having opposing confronting faces 42-and angledouter end portions 44 which are shaped to define sharp points at theouter ends. The mounting portion 46 of this embodiment, however, is astepped, twostage mounting formation providing a first mounting stage 48nearer the rear end of each tip 40 having a flat outer face 480 whichextends in a plane rearwardly converging somewhat relative to the planeof the forwardly convergent faces 42 and is in fact parallel to themedial center plane of the tweezers, and has an aperture 48b forreceiving the mounting screw or stud 30 and has upper and lower parallelsurfaces 48c spaced apart exactly the same distance as the channel sides28a to engage the latter and accurately position the associated tweezertip 40 relative to the arms of the handle portion. The second mountingstage is indicated at 50 and is spaced forwardly from the rear end ofthe associated tweezer tip and includes a flat outer face 500paralleling the medial longitudinal vertical plane of the tweezers, andaperture 50b of the same size as the aperture 48b, and the upper andlower edges of the mounting stage 50 are extensions of the parallelupper and lower surfaces 480. The second stages 50 of the two tweezertips 40 are so located that when the mounting screws 30 are insertedthrough the apertures 50b, the tweezer tips are shortened to a selecteddimension, rendering the tweezers with the tips 40 capable of serving aslong angled point tweezers or short angled point tweezers. as desired bythe user, by merely selecting which of the mounting stages 48, 50 are tobe nested in the channel recesses 28 of the tweezer arms.

it will be appreciated that the changeable tip tweezer constructionherein described provides a convenient and economical precision couplingor mount for the tweezer tips whereby tips of various shapes and sizescan be interchangably mounted on the tweezer arms to fit various userequirements. Furthermore, the tips, being detachable from the handleportions, can be readily made from different. more expensive materialthan the handle portion, and can be precision processed moreconveniently as separate tip portions in appropriate jigs and processingmachines to produce precision tips much more economically than if theywere integrally joined with the flexible handle portions of thetweezers. The mounting channel recesses in the handle portion of the tipare precisely formed preferably by broaching at such angles, when thehandle portion is held in a jig, to define very accurate channels havingbase walls which are disposed in forwardly converging planes disposed atthe proper angle to establish exactly the desired normal angle ofconvergence of the two tip members and which precisely interfit with themounting portions at the rearmost ends of the tip members so as toexactly aline the tip members with each other and resist skewing orsimilar distortions of the tweezer tips. The weight of the heel portionof the tweezer handle and the length of the handle is such that thetweezers are normally readily supported on a work bench or tool tray orother horizontal supporting surface with the heel end 16 and thelowermost portion of the periphery of the two finger discs 32 forming athree-point contact support for the tweezers, with the tip portionsextending outwardly at a slight angle above the horizontal and out ofcontact with the supporting surface. The tweezers are convenientlygrasped by the user by merely grasping the finger discs 32 between twofingers of the users hand, for example the thumb and index finger, withthe pads of the fingers engaging the slightly concave dished circularouter surfaces of the finger discs 32 and with the heel portion 16 ofthe handle engaged by the little finger of the user, insuring highlyeffective and secure control of the tweezers by the user. Thus timelosses from mishandling or fumbling of miniature components to begrasped by the tweezers, as well as costly losses from dropping ofspecially cleaned or fragile items being handled, is minimized by thistweezer construction.

It will be appreciated that a wide variety of tweezer tip configurationsof many sizes, shapes, and types can be removably mounted on the tweezerhandle by the construction of the present invention, as well as variousdesigns of cutter tips having sharp cutting edges or jaws of a number ofconfigurations, and that tips designed especially for shaping,straightening, forming, loop work, stripping, and other desiredfunctions can be conveniently and precisely fixed on the handle portionarms of the present construction in place of the tip configurationsherein shown.

What is claimed is:

l. Changeable tip tweezers comprising a handle portion including a pairof elongated resilient arms having corresponding rearward ends joinedtogether forming a heel end, the arms normally extending in forwardlydiverging relation and having front ends normally disposed in laterallyspaced apart relation, the front end portions of each arm having achannel recess opening through the end surfaces and outer surfacesthereof, the channel recesses having flat base surfaces disposed inselected forwardly convergent planes when the arms occupy their normalforwardly diverging positions and a pair of shoulder surfaces flankingeach base surface, a pair of elongated, forwardly converging removabletip members extending from said front end portions and terminating inforward working ends, said tip members having integral mountingformations at their rearward ends to be respectively nested in saidchannel recesses, the mounting formations having three precision shapedsurfaces including an inner face and a pair of opposing shouldersadjoining the face to be abutted and precisely positioned by said baseand shoulder surfaces of the channel recess for locating the two tipmembers in accurate preselected relative alinement, and threadedfasteners carried by said arms and extending through said mountingformations having manually rotatable head members lying outwardly of thearms to be manipulated for mounting and demounting of the tips on saidarms, said head members having portions projecting beyond the loweredges of the arms adjacent their front ends to define a pair oftransversely spaced rest surfaces coactive with the heel end portion toprovide three-point support of the tweezers on a horizontal surface.

2. Changeable tip tweezers as defined in claim 1, wherein said channelrecesses are of wedge shaped configuration providing triangular upperand lower surfaces defining said opposing shoulders having their apicespointing toward the heel end.

3. Changeable tip tweezers comprising a handle portion including a pairof elongated resilient arms having corresponding rearward ends joinedtogether forming a heel end, the arms normally extending in forwardlydiverging relation and having front ends normally disposed in laterallyspaced apart relation, the front end portions of each arm having achannel recess opening through the end surfaces and outer surfacesthereof, the channel recesses having flat base surfaces disposed inselected forwardly convergent planes when the arms occupy their normalforwardly diverging positions and a pair of shoulder surfaces flankingeach base surface, a pair of elongated, forwardly converging removabletip members extending from said front end portions and terminating inforward working ends, said tip members having integral mountingformations at their rearward ends to be respectively nested in saidchannel recesses, the mounting formations having three precision shapedsurfaces including an inner face and a pair of opposing shouldersadjoining the face to be abutted and precisely positioned by said baseand shoulder surfaces of the channel recess for locating the two tipmembers in accurate preselected relative alinement, and threadedfasteners carried by said arms and extending through said mountingformations having manually rotatable head members lying outwardly of thearms to be manipulated for mounting and demounting of the tips on saidarms, said head members being circular threaded members of greaterdiameter than the maximum transverse dimension of each tweezer armproviding enlarged finger discs to be engaged by the user's fingers andthe circular edges of which define a pair of rest surfaces coactive withthe heel end portion to provide three-point support of the tweezers on ahorizontal surface.

4. Changeable tip tweezers as defined in claim 3, wherein said channelrecesses are of wedge shaped configuration providing triangular upperand lower surfaces defining said opposing shoulders having their apicespointing toward the heel end.

5. Changeable tip tweezers as defined in claim 3, wherein said tipmembers each have two-stage mounting formations of stepped configurationat their rearward ends, the stages providing a pair of apertured stageformations shaped to precisely nest into the companion channel recessesof the tweezer arms at two lon- 8 gitudinally spaced positions andproviding outwardly facing flat landings which lie in parallel planeswhen the arms occupy their normal positions to be abutted by restrainingsurface portions of said head members.

6. Changeable tip tweezers as defined in claim 1, wherein said channelrecesses are of wedge shaped configuration providing triangular upperand lower surfaces defining said opposing shoulders having their apicespointing toward the heel end and said shoulders being in parallel planesperpendicular to the base surface therebetween and parallel to thelongitudinal center axis of the tweezers.

7. Changeable tip tweezers as defined in claim 6, wherein said tipmembers each have two-stage formations of stepped configuration at theirrearward ends, the stages providing a pair of apertured stage formationsshaped to precisely nest into the companion channel recesses of thetweezer arms at two longitudinally spaced positions and providingoutwardly facing flat landings which lie in parallel planes when thearms occupy their normal positions to be abutted by restraining surfaceportions of said head members.

8. Tweezers, comprising a pair of elongated elements defining a handleportion fonned of a pair of elongated resilient arm portions havingcorresponding rearward ends joined together forming a heel end, the armportions normally extending in forwardly diverging relation and havingportions intermediate the length of the tweezers normally disposed inlaterally spaced apart relation, said tweezers including a pair ofelongated, forwardly converging tip portions extending from saidintermediate portions to the working end of the tweezers and terminatingin working points, said tip portions being joined to said arm portionsand positioned in accurate preselected relative alignment, and a pair ofmanually rotatable head members lying outwardly of the arm portionsthreadedly mounted thereto at said intermediate portions, said headmembers forming threaded members having edge portions projecting beyondthe lower edges of said arm portions at said intermediate portions todefine a pair of transversely spaced rest surfaces coactive with theheel end portion to provide three-point support of the tweezers on ahorizontal surface.

9. Tweezers as defined in claim 8, wherein said threaded members arecylindrical members of greater diameter than the maximum transversedimension of each tweezer arm portion and have outwardly concavesurfaces providing enlarged finger discs to be engaged by the usersfingers and the circular edges of which define said pair of restsurfaces.

1. Changeable tip tweezers comprising a handle Portion including a pairof elongated resilient arms having corresponding rearward ends joinedtogether forming a heel end, the arms normally extending in forwardlydiverging relation and having front ends normally disposed in laterallyspaced apart relation, the front end portions of each arm having achannel recess opening through the end surfaces and outer surfacesthereof, the channel recesses having flat base surfaces disposed inselected forwardly convergent planes when the arms occupy their normalforwardly diverging positions and a pair of shoulder surfaces flankingeach base surface, a pair of elongated, forwardly converging removabletip members extending from said front end portions and terminating inforward working ends, said tip members having integral mountingformations at their rearward ends to be respectively nested in saidchannel recesses, the mounting formations having three precision shapedsurfaces including an inner face and a pair of opposing shouldersadjoining the face to be abutted and precisely positioned by said baseand shoulder surfaces of the channel recess for locating the two tipmembers in accurate preselected relative alinement, and threadedfasteners carried by said arms and extending through said mountingformations having manually rotatable head members lying outwardly of thearms to be manipulated for mounting and demounting of the tips on saidarms, said head members having portions projecting beyond the loweredges of the arms adjacent their front ends to define a pair oftransversely spaced rest surfaces coactive with the heel end portion toprovide threepoint support of the tweezers on a horizontal surface. 2.Changeable tip tweezers as defined in claim 1, wherein said channelrecesses are of wedge shaped configuration providing triangular upperand lower surfaces defining said opposing shoulders having their apicespointing toward the heel end.
 3. Changeable tip tweezers comprising ahandle portion including a pair of elongated resilient arms havingcorresponding rearward ends joined together forming a heel end, the armsnormally extending in forwardly diverging relation and having front endsnormally disposed in laterally spaced apart relation, the front endportions of each arm having a channel recess opening through the endsurfaces and outer surfaces thereof, the channel recesses having flatbase surfaces disposed in selected forwardly convergent planes when thearms occupy their normal forwardly diverging positions and a pair ofshoulder surfaces flanking each base surface, a pair of elongated,forwardly converging removable tip members extending from said front endportions and terminating in forward working ends, said tip membershaving integral mounting formations at their rearward ends to berespectively nested in said channel recesses, the mounting formationshaving three precision shaped surfaces including an inner face and apair of opposing shoulders adjoining the face to be abutted andprecisely positioned by said base and shoulder surfaces of the channelrecess for locating the two tip members in accurate preselected relativealinement, and threaded fasteners carried by said arms and extendingthrough said mounting formations having manually rotatable head memberslying outwardly of the arms to be manipulated for mounting anddemounting of the tips on said arms, said head members being circularthreaded members of greater diameter than the maximum transversedimension of each tweezer arm providing enlarged finger discs to beengaged by the user''s fingers and the circular edges of which define apair of rest surfaces coactive with the heel end portion to providethree-point support of the tweezers on a horizontal surface. 4.Changeable tip tweezers as defined in claim 3, wherein said channelrecesses are of wedge shaped configuration providing triangular upperand lower surfaces defining said opposing shoulders having their apicespointing toward the heel end.
 5. Changeable tip tweezers as defined inClaim 3, wherein said tip members each have two-stage mountingformations of stepped configuration at their rearward ends, the stagesproviding a pair of apertured stage formations shaped to precisely nestinto the companion channel recesses of the tweezer arms at twolongitudinally spaced positions and providing outwardly facing flatlandings which lie in parallel planes when the arms occupy their normalpositions to be abutted by restraining surface portions of said headmembers.
 6. Changeable tip tweezers as defined in claim 1, wherein saidchannel recesses are of wedge shaped configuration providing triangularupper and lower surfaces defining said opposing shoulders having theirapices pointing toward the heel end and said shoulders being in parallelplanes perpendicular to the base surface therebetween and parallel tothe longitudinal center axis of the tweezers.
 7. Changeable tip tweezersas defined in claim 6, wherein said tip members each have two-stageformations of stepped configuration at their rearward ends, the stagesproviding a pair of apertured stage formations shaped to precisely nestinto the companion channel recesses of the tweezer arms at twolongitudinally spaced positions and providing outwardly facing flatlandings which lie in parallel planes when the arms occupy their normalpositions to be abutted by restraining surface portions of said headmembers.
 8. Tweezers, comprising a pair of elongated elements defining ahandle portion formed of a pair of elongated resilient arm portionshaving corresponding rearward ends joined together forming a heel end,the arm portions normally extending in forwardly diverging relation andhaving portions intermediate the length of the tweezers normallydisposed in laterally spaced apart relation, said tweezers including apair of elongated, forwardly converging tip portions extending from saidintermediate portions to the working end of the tweezers and terminatingin working points, said tip portions being joined to said arm portionsand positioned in accurate preselected relative alignment, and a pair ofmanually rotatable head members lying outwardly of the arm portionsthreadedly mounted thereto at said intermediate portions, said headmembers forming threaded members having edge portions projecting beyondthe lower edges of said arm portions at said intermediate portions todefine a pair of transversely spaced rest surfaces coactive with theheel end portion to provide three-point support of the tweezers on ahorizontal surface.
 9. Tweezers as defined in claim 8, wherein saidthreaded members are cylindrical members of greater diameter than themaximum transverse dimension of each tweezer arm portion and haveoutwardly concave surfaces providing enlarged finger discs to be engagedby the user''s fingers and the circular edges of which define said pairof rest surfaces.